The Government files from 1983 are the first records to be declassified under
the new “20-year rule” which means that official papers will be made public
sooner.

Previously the documents remained secret for 30 years and were released by the National Archives in Kew, west London, at the end of every year.

The change to the rules means that two years worth of records will be made available each year from now until 2022 in order to catch up with the backlog of files. Documents from 1984 will be declassified in December this year.

After that the National Archives will revert to a single annual release of Government papers.

Releasing the records 10 years earlier will cost up to £38.5 million over the transition period, the Ministry of Justice said last month.

Lord McNally, the minister responsible for archives, said at the time: "The change to a 20-year rule is a key part of our transparency agenda and will see a wealth of historical material opened to the public much earlier than under current arrangements.